1. Field of the Invention
The present invention relates to container for flowable food packaging. Specifically, the present invention relates to tetrahedral top cartons and carton blanks therefor.
2. Description of the Related Art
Gable top cartons have been known for the better part of the twentieth century. Their characteristic simplicity and resealability have helped to sustain their popularity as containers for traditional liquid food products such as milk and juice, but in recent years they have been used for products ranging from ammunition to Epsom salts. Gable top cartons typically begin as generally rectangular carton blanks made of a laminated paperboard or similar material. The carton blanks are provided with a number of creases to facilitate folding and forming the blank into a rectangular carton having the characteristic gabled top.
When fully folded, filled, and sealed, the gable top cartons included a gabled top structure that engages four side-panels. Traditionally, each side panel is generally perpendicular to each adjacent side panel. The panels are each divided from one another by a single vertical score line extending the entire height of the sidewall. These side panels form the characteristic hollow rectangular body of the container and define the volume of product that a carton may hold.
In accordance with accepted design approaches, the design of a traditional gable top carton to accommodate a specified volume involves adjusting the dimensions of the four sidewalls defining the rectangular body that is to contain the specified volume. Very often, these product volume requirements are specified by the packager and selected from standard volumes that have been deemed accepted in the consumer market for the product (i.e., pint, quart, half gallon, gallon, half liter, liter, etc.). When this design approach is utilized, there exists a generally established relationship between the surface area of the carton blank and the carton volume. The surface area of the carton, and particularly the area of the four sidewalls constituting the bulk of the surface area, is thus generally fixed for a given container volume.
Additional end panel extensions and end panel shapes are often employed to assist in folding and sealing the traditional gable top cartons. These added extensions and shapes result in added carton surface area per unit volume of product. One departure from the typical gable top carton is Sisco, U.S. Pat. No. 2,980,304, for a Paperboard Fluid Container which issued on Apr. 18, 1961. Sisco discloses a pyramid top carton which is adapted to substitute for glass bottles of the 1960s. The pyramid top carton of Sisco is reinforced with added layers to lessen the need for a separate nesting member. It is readily apparent that the Sisco carton does not seek to reduce the material content of a carton. The traditional approaches to gable top carton design have heretofore devoted little effort to optimizing the carton surface area per unit volume of product.